Method of making overlays.



N0. 664,9o9f'i- 'Ptented Ian. I, 1901.

E. VOGEL.

METHOD OF MAKING DVERLAYS.

(Application filed May 14, 1900.]

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ERNST VOGEL, OF BERLIN, GERMANY.

METHOD OF MAKiNG OVERLAYS.

SPECIFICATION forming part of Letters Patent No. 664,909, dated January 1, 1901.

Application filed May 14, L900. Serial No. 16,672. (No specimens.)

To call whom. it may concern:

Be it known that I, ERNST VOGEL, chemical engineer, a subject of the King of Prussia, German Emperor, residing at No. 240 and 241 Friedrichstrasse, in the city of Berlin, in the Kingdom of Prussia, German Empire, have in vented a new and useful Improved Method of Overlaying to be Used in Printing-Presses, of which the following is a specification.

In carrying my invention into etfectl first produce an impression or copy of a printers clich (woodcut, linear etching, autotype, or the like) upon a transparent medium, such as paper gelatin, celluloid, or the like. The positive thus obtained is by aid of light copied and developed upon a copper, brass, zinc, or other metal plate, or, if desired, upon stone, in just the same manner as is made use of in the manufacture of high etchings or inv the art of acrography, respectively, and also the same sensitive substancessuch as asphalt, chrome albumen, chrome gum, chrome-gelatin, chrome-glue, or, if desired, mixtures of such substances-are employed.

In the drawings, Figure 1 represents conventionally a printers cliche or engraving having lines in relief. Fig. 2 represents an impression taken therefrom upon a sheet of transparent celluloid. Fig. 3 represents a negative taken from the imprinted celluloid sheet upon a plate of metal or other material. Fig. 4 is the same metal plate after it has been etched by the action of acids; and Fig. 5 represents a sheet of paper intended for overlay in printing-presses which has taken up lines of gelatin or other substance from the previously-filled depressed lines of the metal plate.

As indicated above, an impression is first taken from the clich A upon a sheet of celluloid or other suitable transparent medium B, the raised lines a of the cliche being reproduced in black lines I) on the sheet of celluloid. This impression upon the celluloid acid-resisting surfaces or lines. There results thus a negative copythat is to say, the metal or the stone is free or uncovered at all those places which correspond to the black parts of the positive, whereas the other places, that correspond to the transparent parts of the positive, are covered by the remaining layer of asphalt, chrome-albumen, chrome-gum, chrome-gelatin, chrome-glue, &c., the respective substance having become insoluble in consequence of the action of the light.

Instead of copying directly upon metal or stone the positive may also be copied upon photolithographic paper or pigment-paper, and the copy may then be transferred upon the metal or stone and developed in known manner.

When the metal plate or stone plate, after having been prepared in the aforedescribed way, is introduced into a solntionsuch as an acid, ferric chlorid, or the likewhich is capable of dissolving the respective metal, then the respective solution can exert such an action only at those places of the metal or stone which are free of the above-mentioned layer, because at all the other places the solution is prevented from such action by the insoluble parts of said layer. There is thus obtained a plate D in relief, in which, contrary to an ordinary printing-cliche, those parts d, which correspond to the black places of the. positive, appear in cavetto, Whereas the other parts cl, that correspond to the light places of the positive, appear in relief. This relief is the deeper the longer the etching medium has been allowed to act upon the plate. Molten gelatin is now poured over the etched plate, and a sheet of paper or other pliable medium E is placed thereon and the Whole subjected to a moderate pressure in a press. After the gelatin has stifiened, the sheet may be taken 05 the plate and dried, the gelatin from the depressed lines of the plate adhering to it and forming relief lines 6, corresponding to the relief lines of the original cut or clich, and adapting the sheet to serve as overlay in a printing-press.

The gelatin may be replaced by celluloid, papier-mach, caoutchouc, gutta-percha, or another suited material, and, if necessary,

etched surface with melted gelatin, placing a pliable sheet thereon, and subjecting the Whole to the action of a press, until the gelatin has stiffened, then removing said sheet with the gelatin adhering thereto in relief lines, and drying it.

In witness whereof hand in presence of two witnesses.

ERNST VOGEL.

Witnesses:

WOLDEMAR 'HAUPT, HENRY HASPER.

I have hereunto set my 20 

